1. Field of the Invention
The present invention relates to a heat exchanger, and is effectively applied to an inter-cooler to cool air (suction air) used for combustion sucked into an internal combustion engine.
2. Description of the Related Art
FIG. 1 is a front view showing an inter-cooler produced by way of trial and investigated by the present inventors. This inter-cooler includes: tubes 111 in which suction air flows; fins 112 for facilitating heat-exchange between cooling air and suction air; and header tanks 120 communicating with the tubes 111. As shown in FIG. 6, the header tanks 120 include: core plates 121 made of aluminum to which the tubes 111 are soldered; and a tank body 122 made of resin which constitutes a space in the tank being calked to the core plate 121.
In this inter-cooler produced by way of trial production, as shown in FIGS. 6 and 7, while the forward end portion 122a of the tank body 122 is being inserted into the groove portion 121a of the core plate 121, a forward end side of the protruding portion (pawl portion) 121b used for calking, which is provided on the core plate 121, is plastically deformed being bent onto the tank body 122 side, so that the tank body 122 and the core plate 121 are calked and fixed to each other.
In this connection, in order to enhance the pressure-withstanding strength of the inter-cooler, it is necessary to increase the wall thickness of parts such as the core plate 121 composing the inter-cooler. However, when the wall thickness of the core plate 121 is increased, the bending rigidity of the pawl portion 121b is increased. Accordingly, there is a possibility that the workability of the calking (bending work of bending the pawl portion 121b) will deteriorate.
On the other hand, when length L of the pawl portion 121b (length from the forward end of the pawl portion to the bent portion 121c) is extended, it is possible to generate a high bending moment in the bent portion by a relatively low-intensity force. Therefore, even if the wall thickness of the core plate 121 is large, it is possible to prevent the workability of the calking from deteriorating.
However, when the above means is adopted, length L of the pawl portion is extended. Therefore, width (thickness of the inter-cooler) W of the core plate 121 is increased, which degrades the mounting performance of the inter-cooler when the inter-cooler is mounted on a vehicle.